Cleaning Q&A - How to Clean a Coffee Thermos

Cleaning Q&A
Today's Question: How to Clean a Coffee Thermos

I just received an email from George E that I wanted to share with all of you. He was asking a question that I thought many of you might want the answer to...

"Hi Christina,

Thank you for helping all of us to live a cleaner life while not costing us an arm or a leg.

I have a question regarding cleaning the white plastic parts of a glass coffee pot (lid) and a white plastic coffee thermos. I have looked on your web site as well as our own Arizona "Queen of Clean" but have not found any suggestions.

What suggestions do you have?

Thank you. keep up your very good work!

Warm regards,
George E."


Hi George,

First, thank you for such a nice email. I remember conversing via email with you before, and you're always a real gent. Now, on to your question -- how to clean those pesky (although entirely useful) Thermos containers!? So many of us rely on these to tote hot coffee or tea, or even hot soups and stews to work for our lunch. But, as you've noticed, they can be downright tricky to clean.

To find the best, and most helpful answer for you, George, I did a little research. I checked on the offical Thermos website, and found some of these tips that I think will come in very handy for you:

1. First of all, use the gentlest cleanser possible for your Thermos® products, especially those made of stainless steel. Harsh, abrasive cleaners and scrubbers can tarnish Food Jars and drink containers, and could even begin to change the flavor of stored foods after a while. A dishwashing detergent or gentle all-purpose cleanser or soap that is safe for dishes should be sufficient (i.e. Joy, Dawn). If you have to use an abrasive pad, make sure that it's made out of plastic so that it won't scrape the inside of the product, and scrub lightly.
2. Cleaning your Thermos® products will also be much easier if you clean after every use. If you've prepared a meal for a Food Jar, soak the jar for a few minutes before cleaning to remove any food residue that you may have difficulty removing with a washcloth. If you want to clean certain stains off of food containers, a soft toothbrush may do the trick; dip the brush in a little bit of detergent and gently scrub the rim and bottom of the cup to remove residue. Many people also use gentle baby's soap or hypo-allergenic laundry detergent along with or instead of dishwashing detergent to clean Thermos® products, because it preserves the shine of a Food Jar or mug, and can remove food easily.
3. Cleaning smudges or fingerprints from your stainless steel Thermos® products is easy as well, since most smudges will come out by using slightly damp paper towel or a sponge. For extremely stubborn stains, try soaking the Thermos® product in warm water with detergent for a little while longer, then rinse again with water and vinegar or water and phosphoric acid. This helps to remove stubborn food stains like grape juice, tomato, and coffee stains. Soaking Thermos® products with warm water and baking soda, or even ammonia in some cases will get rid of tough stains.

Some of the Happy Slob's Additional Cleaning Tips:

• The most stubborn part of cleaning a Thermos is, of course, getting a proper cleaning brush or sponge that can reach down to the bottom. I have found the perfect solution -- a wine decanter cleaner brush! Never heard of this? It does exactly what it's name implies -- cleans out wine decanters. It is a long, narrow cleaning sponge that is gentle to the delicate glass or crystal of wine decanters, therefore also making it perfect for your Thermos containers. You can find these to purchase online or at specialty wine shops, or even cooking shops. (We sell them at the store where I work, for instance.) I also happened to find some cleaning sponges/brushes especially for Thermos products! I'll post the pics to those too...

• Cleaning stainless steel is a snap with my favorite commercial cleaner - Barkeepers Friend. I like the liquid version best, but the powder is so finely milled that it also will never scratch the delicate surface of stainless steel. Once you try this stuff, you'll be just as hooked as I am. (All Clad, the posh cookware brand, also recommends it for their top end pots and pans...so that also gives you assurance that this stuff really works.)
• Cleaning stains is also easy -- just let some vinegar diluted with water (about half and half, more vinegar if it's a really tough stain) sit in the Thermos for about an hour or so. Then use the same wine decanter cleaning sponge/brush to scrub the stain away. :) Voila, clean Thermos -- ready to fill with your favorite hot drink!

Hope this helps, George, and everyone else who has ever faced this particular cleaning dilemma. Happy cleaning to you!

Christina